An Irish nanny accused of murdering a Massachusetts baby has been denied a reduction in bail that would allow her release after a US judge ruled that new medical evidence was not enough to weaken the prosecution’s case against her.

Judge S Jane Haggerty said there was not “sufficient change” in new evidence, showing that Rehma Sabir most likely suffered spine fractures three to four weeks before her death when she was not in the care of Irish woman Aisling Brady McCarthy, to warrant a reduction in bail from $500,000 to $5,000.

The judge said that there had been “missteps” by prosecutors in the case leading to the delays in medical evidence being made available to the defence but that they did not merit a reduction in bail.

Lawyers for Mrs Brady McCarthy (35) had asked the court to facilitate her release by substantially reducing the nanny’s bail on the basis of the new evidence from the prosecution’s experts that cast doubt on her guilt in the death and in light of delays in the evidence being available to the defence.

The woman, who is originally from Co Cavan, attended the court hearing in Woburn near Boston dressed in black. She has pleaded not guilty to the first-degree murder of the baby who was hospitalised with severe head injuries on her first birthday in January 2013 and died two days later.

Prosecutors allege that the Irish woman was the only one caring for the child when the fatal injuries occurred. Her defence team claims that the baby had suffered previous bone injuries from the time when she was travelling overseas and not being looked after by the nanny.

Speaking at a pre-trial status hearing, Judge Haggerty said that she accepted the prosecution’s argument that “all along the main focus here has been on the head injury” and that factures to the child’s “long bones” and the thoracic vertebral bones (in the middle of her back) were “really open.”

Now that these fractures have been narrowed to having most likely taken place between three to four weeks before the child’s death, this “gives the defence more information to work with,” said the judge.

“I do not believe that the government’s case has been substantially diminished such that I would allow a reduction in the bail,” she added.

On an application for lower bail because of the 13-month delay in medical evidence being made available, the judge denied the request, saying that there can be delays in these kinds of cases.

“Many of these things do take time,” she said.

“There have clearly been some missteps by the government, not intentionally in my view, but not sufficiently egregious in this type of case where the medical evidence is really critical.”

The Irish woman’s attorney David Meier sought to delay the start of the murder trial, saying there was “no way” this case was going to trial as scheduled on April 7th because of the delays and asked the judge to reconsider bail.

Mr Meier requested that the court consider the delays in the discovery in the case and that in the interest of fairness and due process that Mrs Brady McCarthy be given an opportunity to post bail.

Prosecutors have warned that Mrs Brady McCarthy, who has been detained for 13 months, faces deportation if released on bail because she is in the US illegally after outstaying a visa issued in 2002.

The judge told prosecutors that she would reconsider her decision not to reduce bail if there were further delays in 72 retinal slides being made available to Mrs Brady McCarthy’s defence team.

There was a lengthy discussion about the status of the slides and at one point the judge adjourned the hearing to determine when the slides would be sent back to Boston from a doctor in Florida.

The judge adjourned the case until Monday afternoon at 2pm to allow prosecutors to speak to the doctor, who has been on leave since February 14th, to determine when the slides will become available.

The defence also asked that the prosecution provide further information on 32 or 33 doctors or physicians listed by the prosecution out of 90 potential witnesses that might be called during the trial.